Make things work with multipart keys.

app/controllers/api_controller.rb

@@ -161,7 +161,7 @@ class ApiController < ApplicationController
     ways = Array.new
     if node_ids.length > 0
       way_nodes = WayNode.find_all_by_node_id(node_ids)
-      way_ids = way_nodes.collect {|way_node| way_node.id }
+      way_ids = way_nodes.collect {|way_node| way_node.id[0] }
       ways = Way.find(way_ids)
 
       list_of_way_nodes = ways.collect { |way|

app/models/old_way.rb

@@ -38,15 +38,13 @@ class OldWay < ActiveRecord::Base
       tag.save!
     end
 
-    i = 1
+    sequence = 1
     self.nds.each do |n|
       nd = OldWayNode.new
-      nd.id = self.id
+      nd.id = [self.id, self.version, sequence]
       nd.node_id = n
-      nd.sequence_id = i
-      nd.version = self.version
       nd.save!
-      i += 1
+      sequence += 1
     end
   end
 

app/models/old_way_node.rb

@@ -1,6 +1,5 @@
 class OldWayNode < ActiveRecord::Base
-  belongs_to :user
-
   set_table_name 'way_nodes'
 
+  set_primary_keys :id, :version, :sequence_id
 end

app/models/way.rb

@@ -177,14 +177,13 @@ class Way < ActiveRecord::Base
 
       WayNode.delete_all(['id = ?', self.id])
 
-      i = 1
+      sequence = 1
       nds.each do |n|
         nd = WayNode.new
-        nd.id = self.id
+        nd.id = [self.id, sequence]
         nd.node_id = n
-        nd.sequence_id = i
         nd.save!
-        i += 1
+        sequence += 1
       end
     end